Reduced length valve assembly with ultrasonic flow sensor

ABSTRACT

A system for controlling a flow rate of a fluid through a valve includes a controller. The controller is configured to receive a raw flow rate measurement from a flow rate sensor assembly configured to measure the flow rate. The controller is further configured to apply a flow rate measurement filter to the raw flow rate measurement to generate a filtered flow rate measurement. The controller is further configured to control actuation of an actuator configured to change the flow rate using the filtered flow rate measurement. The controller is configured to automatically adjust the flow rate measurement filter in response to detecting an event that causes stoppage of the actuation of the actuator.

BACKGROUND

The present disclosure relates generally to the field of buildingmanagement systems and associated devices and more particularly to anassembly with a reduced length valve coupled to an ultrasonic flowsensor. The assembly includes a valve that regulates a flow of a fluidthrough a conduit, pipe, or tube depending on a setpoint controlled by aflow value output actuator. The actuator determines the setpoint basedon sensing data provided by a flow sensor. Existing flow sensorassemblies are arranged upstream or downstream in reference to the valvealong with conduit (e.g. straight pipe) in between the valve and sensorto ensure accurate sensor readings. Because the conduit increases theoverall size of the valve assembly and increases the number of parts inthe assembly, it would be advantageous to decrease or eliminate theconduit while maintaining accurate flow sensor data.

The flow sensor assembly typically includes one or more transducers withacoustic reflectors. Many existing HVAC flow sensors are largelydependent on a distance variable, L, between the acoustic reflectors tocontrol the signal-to-noise-ratio (“S/N”). Minimizing L would bedesirable from a cost, handling, and installation point of view.

SUMMARY

One implementation of the present disclosure is a system for controllinga flow rate of a fluid through a valve, according to some embodiments.In some embodiments, the system includes a controller. In someembodiments, the controller is configured to receive a raw flow ratemeasurement from a flow rate sensor assembly configured to measure theflow rate. In some embodiments, the controller is further configured toapply a flow rate measurement filter to the raw flow rate measurement togenerate a filtered flow rate measurement. In some embodiments, thecontroller is further configured to control actuation of an actuatorconfigured to change the flow rate using the filtered flow ratemeasurement. In some embodiments, the controller is configured toautomatically adjust the flow rate measurement filter in response todetecting an event that causes stoppage of the actuation of theactuator.

In some embodiments, the controller is further configured to controlactuation of the actuator using the raw flow rate measurement for flowrate measured during actuation of the actuator to change the flow rateand using the filtered flow rate measurement for flow rate measuredduring stoppage of the actuation of the actuator.

In some embodiments, the flow rate measurement filter includes a memoryof previously recorded values of the flow rate and the controller isconfigured to reset the flow rate measurement filter by updating one ormore parameters of a process noise covariance matrix in response todetecting the event that causes stoppage of the actuation of theactuator.

In some embodiments, adjusting the flow rate measurement filter includesclearing a memory of previously recorded values of the flow rate so thatthe previously recorded values of the flow rate are not used by the flowrate measurement filter to generate the filtered flow rate measurement.

In some embodiments, the flow rate sensor assembly includes a firstultrasonic transducer and a second ultrasonic transducer.

In some embodiments, the first ultrasonic transducer and the secondultrasonic transducer are located such that a first portion of a flowpath between the first ultrasonic transducer and the second ultrasonictransducer is parallel to the flow of fluid, and a second portion of theflow path between the first ultrasonic transducer and the secondultrasonic transducer is perpendicular to the flow of fluid.

In some embodiments, the first ultrasonic transducer and the secondultrasonic transducer are located such that the flow of fluid passesbetween the first ultrasonic transducer and the second ultrasonictransducer.

In some embodiments, a flow path between the first ultrasonic transducerand the second ultrasonic transducer is positioned at a first anglerelative to the flow of fluid.

Another implementation of the present disclosure is an ultrasonic flowsensor assembly configured to measure a flow of fluid through a conduit,according to some embodiments. In some embodiments, the ultrasonic flowsensor assembly includes a first and second ultrasonic transducer and aprocessing circuit. In some embodiments, the first and second ultrasonictransducers are fixedly coupled with the conduit and separated from eachother by a distance less than or substantially equal to twice a diameterof the conduit. In some embodiments, the processing circuit isconfigured to operate the first ultrasonic transducer to emit anultrasonic signal along a flow path of the fluid in the conduit byproviding a voltage or current to the first ultrasonic transducer. Insome embodiments, the processing circuit is also configured to receive avoltage or current from the second ultrasonic transducer in response tothe second ultrasonic transducer receiving the ultrasonic signal emittedby the first ultrasonic transducer. In some embodiments, the processingcircuit is also configured to obtain a raw measurement of a flow rate ofthe fluid in the conduit using the received voltage or current. In someembodiments, the processing circuit is configured to generate a filteredmeasurement of the flow rate of the fluid using a filter and the rawmeasurement.

In some embodiments, the ultrasonic flow sensor assembly furtherincludes a structural member, separate from the conduit. In someembodiments, the structural extends between the first ultrasonictransducer and the second ultrasonic transducer. In some embodiments,the structural member is fixedly coupled with the first ultrasonictransducer and the second ultrasonic transducer and maintains a fixeddistance between the first ultrasonic transducer and the secondultrasonic transducer.

In some embodiments, the first ultrasonic transducer and the secondultrasonic transducer are each configured to receive an ultrasonicsignal within the conduit and convert the received ultrasonic signal toa voltage or current. In some embodiments, the first ultrasonictransducer and the second ultrasonic transducer are each also configuredto receive a voltage or current and emit an ultrasonic signal at leastpartially along the flow path of the fluid in the conduit.

In some embodiments, the ultrasonic flow sensor assembly also includesan actuator operatively coupled with the processing circuit. In someembodiments, the processing circuit is configured to operate theactuator to affect the flow rate of the fluid through the conduit usingthe filtered measurement of the flow rate of the fluid.

In some embodiments, the processing circuit is configured to use thefiltered measurement of the flow rate of the fluid to operate theactuator when the actuator is within a position setpoint plus or minus adeadband and maintain a current value of the position setpoint when theactuator is outside of the deadband of the position setpoint.

In some embodiments, the processing circuit is configured to reset thefilter in response to the actuator reaching a position setpoint or inresponse to an event that causes stoppage of the actuator. In someembodiments, resetting the filter includes clearing a memory of thefilter of previously obtained values of the raw measurement of the flowrate.

In some embodiments, clearing the memory includes adjusting one or moreparameters of the filter.

In some embodiments, the ultrasonic flow sensor assembly furtherincludes a first acoustic reflector and a second acoustic reflector. Insome embodiments, the first and second acoustic reflectors areconfigured to cooperatively direct the ultrasonic signal emitted by thefirst ultrasonic transducer along the flow path of the fluid and to thesecond ultrasonic transducer.

In some embodiments, the first ultrasonic transducer and the secondultrasonic transducer are oriented to emit and receive the ultrasonicsignal in a direction perpendicular to the flow path of the fluid.

In some embodiments, the first ultrasonic transducer and the secondultrasonic transducer are positioned on opposite sides of the conduitand the first ultrasonic transducer is configured to emit the ultrasonicsignal towards the second ultrasonic transducer along a path angularlyoffset from the flow path of the fluid.

Another implementation of the present disclosure is a method formeasuring a flow rate of fluid through a conduit, according to someembodiments. In some embodiments, the method includes measuring the flowrate of the fluid and generating a raw flow rate measurement. In someembodiments, the method also includes applying a flow rate measurementfilter to the raw flow rate measurement to generate a filtered flow ratemeasurement. In some embodiments, the method includes controllingactuation of an actuator to change the flow rate using the filtered flowrate measurement. In some embodiments, the method includes automaticallyadjusting the flow rate measurement filter in response to detecting anevent that causes stoppage of the actuation of the actuator.

In some embodiments, the method further includes controlling actuationof the actuator using the raw flow rate measurement for flow ratemeasured during actuation of the actuator to change the flow rate andusing the filtered flow rate measurement for flow rate measured duringstoppage of the actuation of the actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing of a building equipped with a heating, ventilating,or air conditioning (HVAC) system and a building management system(BMS), according to some embodiments.

FIG. 2 is a schematic diagram of a waterside system that can be used tosupport the HVAC system of FIG. 1, according to some embodiments.

FIG. 3 is a block diagram of an airside system that can be used as partof the HVAC system of FIG. 1, according to some embodiments.

FIG. 4 is a block diagram of a BMS that can be implemented in thebuilding of FIG. 1, according to some embodiments.

FIG. 5 is a schematic diagram of an electronic pressure-independentcontrol valve assembly that can be implemented in the HVAC system ofFIG. 1, according to some embodiments.

FIG. 6 is a block diagram of a signal filtering pressure disturbancerejection valve assembly that can be implemented in the HVAC system ofFIG. 1, according to some embodiments.

FIG. 7 is a block diagram of a pressure disturbance rejection valveassembly within a feedback control system that can be implemented in theHVAC system of FIG. 1, according to some embodiments.

FIG. 8 is a schematic diagram of an ultrasonic flow sensor assembly thatcan be implemented in the electronic pressure-independent control valveassembly of FIG. 5, according to some embodiments.

FIG. 9 is a schematic diagram of a downstream arrangement of avalve-coupled ultrasonic electronic pressure-independent controlassembly that can be implemented in the HVAC system of FIG. 1, accordingto some embodiments.

FIG. 10 is a schematic diagram of an upstream arrangement of avalve-coupled ultrasonic electronic pressure-independent controlassembly that can be implemented in the HVAC system of FIG. 1, accordingto some embodiments.

FIG. 11 is a schematic diagram of a mirrored configuration of anultrasonic standalone flow sensor that can be implemented in the HVACsystem of FIG. 1, according to some embodiments.

FIG. 12 is a schematic diagram of a mirrorless configuration of anultrasonic standalone flow sensor that can be implemented in the HVACsystem of FIG. 1, according to some embodiments.

FIG. 13 is a flow diagram of a process for operating a valve-coupledultrasonic electronic pressure-independent control assembly, accordingto some embodiments.

FIG. 14 is a flow diagram of a process for filtering a flow measurement,according to some embodiments.

FIG. 15 is a graph of volumetric flow rate versus samples for any of theultrasonic flow sensor assemblies of FIGS. 8-12 showing an effect offiltering a signal associated with the volumetric flow rate, accordingto some embodiments.

FIG. 16 is a graph of volumetric flow rate versus samples for any of theultrasonic flow sensor assemblies of FIGS. 8-12 showing an effect offlow offset correction, according to some embodiments.

FIG. 17 is a graph of volumetric flow rate versus samples for any of theultrasonic flow sensor assemblies of FIGS. 8-12 showing an effect offilter enable/disable on signal response time, according to someembodiments.

DETAILED DESCRIPTION Overview

Before turning to the FIGURES which illustrate example embodiments, itshould be understood that the application is not limited to the detailsor methodology set forth in the following description or illustrated inthe FIGURES. It should also be understood that the phraseology andterminology employed herein is for the purpose of description only andshould not be regarded as limiting. For example, the embodiments ofsystems and methods discussed herein can be relevant to any of a varietyof circumstances when operating a control valve assembly can be useful.

The embodiments and implementation of the systems and methods disclosedherein improve current HVAC systems by developing an alternate solutionto placing conduit in between a valve body and a flow sensor body.Current systems are generally configured to require conduit prior to theflow sensor body such that an accurate flow measurement can be achieved.However, implementation of the conduit increases the overall size andnumber of parts required in the valve assembly. Accordingly, systems andmethods disclosed herein enable a customer to eliminate the requirementof conduit (e.g. straight pipe) before the flow sensor body.

The embodiments disclosed herein further improve current HVAC systems bydeveloping an alternate solution to a required distance, L, in a flowsensor assembly that includes an acoustic reflector and a transducer.Current systems are generally configured to require the flow sensorassembly to have the distance L between the acoustic reflectors, suchthat an accurate flow measurement can be achieved. Distance L isnecessary to control a signal-to-noise-ratio (“S/N”), which will varydepending on a conduit diameter, D. However, implementation of thedistance, L, can increase the overall size of the valve assembly, whichmay make installation in some locations difficult. Accordingly, systemsand methods disclosed herein enable a customer to eliminate therequirement of distance, L between the acoustic reflectors allowing anoverall shorter sensor body without losing control of the S/N. As such,the systems, and methods implementations disclosed herein improve costsavings, current handling and installation methods, and compliance byproviding functionalities that are novel and non-obvious improvementsover current systems.

Building and HVAC System

Referring to FIGS. 1-4, an exemplary BMS and HVAC system in which thesystems and methods of the present disclosure can be implemented areshown, according to some embodiments. Referring particularly to FIG. 1,a perspective view of a building 10 is shown. Building 10 is served by aBMS. A BMS is, in general, a system of devices configured to control,monitor, and manage equipment in or around a building or building area.A BMS can include, for example, a HVAC system, a security system, alighting system, and a fire alerting system, any other system that iscapable of managing building functions or devices, or any combinationthereof.

The BMS that serves building 10 includes an HVAC system 100. HVAC system100 may include a plurality of HVAC devices (e.g., heaters, chillers,air handling units, pumps, fans, thermal energy storage, etc.)configured to provide heating, cooling, ventilation, or other servicesfor building 10. For example, HVAC system 100 is shown to include awaterside system 120 and an airside system 130. Waterside system 120 mayprovide a heated or chilled fluid to an air handling unit of airsidesystem 130. Airside system 130 may use the heated or chilled fluid toheat or cool an airflow provided to building 10. An exemplary watersidesystem and airside system which can be used in HVAC system 100 aredescribed in greater detail with reference to FIGS. 2-3.

HVAC system 100 is shown to include a chiller 102, a boiler 104, and arooftop air handling unit (AHU) 106. Waterside system 120 may use boiler104 and chiller 102 to heat or cool a working fluid (e.g., water,glycol, etc.) and may circulate the working fluid to AHU 106. In variousembodiments, the HVAC devices of waterside system 120 can be located inor around building 10 (as shown in FIG. 1) or at an offsite locationsuch as a central plant (e.g., a chiller plant, a steam plant, a heatplant, etc.). The working fluid can be heated in boiler 104 or cooled inchiller 102, depending on whether heating or cooling is required inbuilding 10. Boiler 104 may add heat to the circulated fluid, forexample, by burning a combustible material (e.g., natural gas) or usingan electric heating element. Chiller 102 may place the circulated fluidin a heat exchange relationship with another fluid (e.g., a refrigerant)in a heat exchanger (e.g., an evaporator) to absorb heat from thecirculated fluid. The working fluid from chiller 102 and/or boiler 104can be transported to AHU 106 via piping 108.

AHU 106 may place the working fluid in a heat exchange relationship withan airflow passing through AHU 106 (e.g., via one or more stages ofcooling coils and/or heating coils). The airflow can be, for example,outside air, return air from within building 10, or a combination ofboth. AHU 106 may transfer heat between the airflow and the workingfluid to provide heating or cooling for the airflow. For example, AHU106 may include one or more fans or blowers configured to pass theairflow over or through a heat exchanger containing the working fluid.The working fluid may then return to chiller 102 or boiler 104 viapiping 110.

Airside system 130 may deliver the airflow supplied by AHU 106 (i.e.,the supply airflow) to building 10 via air supply ducts 112 and mayprovide return air from building 10 to AHU 106 via air return ducts 114.In some embodiments, airside system 130 includes multiple variable airvolume (VAV) units 116. For example, airside system 130 is shown toinclude a separate VAV unit 116 on each floor or zone of building 10.VAV units 116 may include dampers or other flow control elements thatcan be operated to control an amount of the supply airflow provided toindividual zones of building 10. In other embodiments, airside system130 delivers the supply airflow into one or more zones of building 10(e.g., via supply ducts 112) without using intermediate VAV units 116 orother flow control elements. AHU 106 may include various sensors (e.g.,temperature sensors, pressure sensors, etc.) configured to measureattributes of the supply airflow. AHU 106 may receive input from sensorslocated within AHU 106 and/or within the building zone and may adjustthe flow rate, temperature, or other attributes of the supply airflowthrough AHU 106 to achieve setpoint conditions for the building zone.

Referring now to FIG. 2, a block diagram of a waterside system 200 isshown, according to some embodiments. In various embodiments, watersidesystem 200 may supplement or replace waterside system 120 in HVAC system100 or can be implemented separate from HVAC system 100. Whenimplemented in HVAC system 100, waterside system 200 may include asubset of the HVAC devices in HVAC system 100 (e.g., boiler 104, chiller102, pumps, valves, etc.) and may operate to supply a heated or chilledfluid to AHU 106. The HVAC devices of waterside system 200 can belocated within building 10 (e.g., as components of waterside system 120)or at an offsite location such as a central plant.

In FIG. 2, waterside system 200 is shown as a central plant having aplurality of subplants 202-212. Subplants 202-212 are shown to include aheater subplant 202, a heat recovery chiller subplant 204, a chillersubplant 206, a cooling tower subplant 208, a hot thermal energy storage(TES) subplant 210, and a cold thermal energy storage (TES) subplant212. Subplants 202-212 consume resources (e.g., water, natural gas,electricity, etc.) from utilities to serve the thermal energy loads(e.g., hot water, cold water, heating, cooling, etc.) of a building orcampus. For example, heater subplant 202 can be configured to heat waterin a hot water loop 214 that circulates the hot water between heatersubplant 202 and building 10. Chiller subplant 206 can be configured tochill water in a cold water loop 216 that circulates the cold waterbetween chiller subplant 206 building 10. Heat recovery chiller subplant204 can be configured to transfer heat from cold water loop 216 to hotwater loop 214 to provide additional heating for the hot water andadditional cooling for the cold water. Condenser water loop 218 mayabsorb heat from the cold water in chiller subplant 206 and reject theabsorbed heat in cooling tower subplant 208 or transfer the absorbedheat to hot water loop 214. Hot TES subplant 210 and cold TES subplant212 may store hot and cold thermal energy, respectively, for subsequentuse.

Hot water loop 214 and cold water loop 216 may deliver the heated and/orchilled water to air handlers located on the rooftop of building 10(e.g., AHU 106) or to individual floors or zones of building 10 (e.g.,VAV units 116). The air handlers push air past heat exchangers (e.g.,heating coils or cooling coils) through which the water flows to provideheating or cooling for the air. The heated or cooled air can bedelivered to individual zones of building 10 to serve the thermal energyloads of building 10. The water then returns to subplants 202-212 toreceive further heating or cooling.

Although subplants 202-212 are shown and described as heating andcooling water for circulation to a building, it is understood that anyother type of working fluid (e.g., glycol, CO2, etc.) can be used inplace of or in addition to water to serve the thermal energy loads. Inother embodiments, subplants 202-212 may provide heating and/or coolingdirectly to the building or campus without requiring an intermediateheat transfer fluid. These and other variations to waterside system 200are within the teachings of the present disclosure.

Each of subplants 202-212 may include a variety of equipment configuredto facilitate the functions of the subplant. For example, heatersubplant 202 is shown to include a plurality of heating elements 220(e.g., boilers, electric heaters, etc.) configured to add heat to thehot water in hot water loop 214. Heater subplant 202 is also shown toinclude several pumps 222 and 224 configured to circulate the hot waterin hot water loop 214 and to control the flow rate of the hot waterthrough individual heating elements 220. Chiller subplant 206 is shownto include a plurality of chillers 232 configured to remove heat fromthe cold water in cold water loop 216. Chiller subplant 206 is alsoshown to include several pumps 234 and 236 configured to circulate thecold water in cold water loop 216 and to control the flow rate of thecold water through individual chillers 232.

Heat recovery chiller subplant 204 is shown to include a plurality ofheat recovery heat exchangers 226 (e.g., refrigeration circuits)configured to transfer heat from cold water loop 216 to hot water loop214. Heat recovery chiller subplant 204 is also shown to include severalpumps 228 and 230 configured to circulate the hot water and/or coldwater through heat recovery heat exchangers 226 and to control the flowrate of the water through individual heat recovery heat exchangers 226.Cooling tower subplant 208 is shown to include a plurality of coolingtowers 238 configured to remove heat from the condenser water incondenser water loop 218. Cooling tower subplant 208 is also shown toinclude several pumps 240 configured to circulate the condenser water incondenser water loop 218 and to control the flow rate of the condenserwater through individual cooling towers 238.

Hot TES subplant 210 is shown to include a hot TES tank 242 configuredto store the hot water for later use. Hot TES subplant 210 may alsoinclude one or more pumps or valves configured to control the flow rateof the hot water into or out of hot TES tank 242. Cold TES subplant 212is shown to include cold TES tanks 244 configured to store the coldwater for later use. Cold TES subplant 212 may also include one or morepumps or valves configured to control the flow rate of the cold waterinto or out of cold TES tanks 244.

In some embodiments, one or more of the pumps in waterside system 200(e.g., pumps 222, 224, 228, 230, 234, 236, and/or 240) or pipelines inwaterside system 200 include an isolation valve associated therewith.Isolation valves can be integrated with the pumps or positioned upstreamor downstream of the pumps to control the fluid flows in watersidesystem 200. In various embodiments, waterside system 200 may includemore, fewer, or different types of devices and/or subplants based on theparticular configuration of waterside system 200 and the types of loadsserved by waterside system 200.

Referring now to FIG. 3, a block diagram of an airside system 300 isshown, according to some embodiments. In various embodiments, airsidesystem 300 may supplement or replace airside system 130 in HVAC system100 or can be implemented separate from HVAC system 100. Whenimplemented in HVAC system 100, airside system 300 may include a subsetof the HVAC devices in HVAC system 100 (e.g., AHU 106, VAV units 116,ducts 112-114, fans, dampers, etc.) and can be located in or aroundbuilding 10. Airside system 300 may operate to heat or cool an airflowprovided to building 10 using a heated or chilled fluid provided bywaterside system 200.

In FIG. 3, airside system 300 is shown to include an economizer-type airhandling unit (AHU) 302. Economizer-type AHUs vary the amount of outsideair and return air used by the air handling unit for heating or cooling.For example, AHU 302 may receive return air 304 from building zone 306via return air duct 308 and may deliver supply air 310 to building zone306 via supply air duct 312. In some embodiments, AHU 302 is a rooftopunit located on the roof of building 10 (e.g., AHU 106 as shown inFIG. 1) or otherwise positioned to receive both return air 304 andoutside air 314. AHU 302 can be configured to operate exhaust air damper316, mixing damper 318, and outside air damper 320 to control an amountof outside air 314 and return air 304 that combine to form supply air310. Any return air 304 that does not pass through mixing damper 318 canbe exhausted from AHU 302 through exhaust damper 316 as exhaust air 322.

Each of dampers 316-320 can be operated by an actuator. For example,exhaust air damper 316 can be operated by actuator 324, mixing damper318 can be operated by actuator 326, and outside air damper 320 can beoperated by actuator 328. Actuators 324-328 may communicate with an AHUcontroller 330 via a communications link 332. Actuators 324-328 mayreceive control signals from AHU controller 330 and may provide feedbacksignals to AHU controller 330. Feedback signals may include, forexample, an indication of a current actuator or damper position, anamount of torque or force exerted by the actuator, diagnosticinformation (e.g., results of diagnostic tests performed by actuators324-328), status information, commissioning information, configurationsettings, calibration data, and/or other types of information or datathat can be collected, stored, or used by actuators 324-328. AHUcontroller 330 can be an economizer controller configured to use one ormore control algorithms (e.g., state-based algorithms, extremum seekingcontrol (ESC) algorithms, proportional-integral (PI) control algorithms,proportional-integral-derivative (PID) control algorithms, modelpredictive control (MPC) algorithms, feedback control algorithms, etc.)to control actuators 324-328.

Still referring to FIG. 3, AHU 302 is shown to include a cooling coil334, a heating coil 336, and a fan 338 positioned within supply air duct312. Fan 338 can be configured to force supply air 310 through coolingcoil 334 and/or heating coil 336 and provide supply air 310 to buildingzone 306. AHU controller 330 may communicate with fan 338 viacommunications link 340 to control a flow rate of supply air 310. Insome embodiments, AHU controller 330 controls an amount of heating orcooling applied to supply air 310 by modulating a speed of fan 338.

Cooling coil 334 may receive a chilled fluid from waterside system 200(e.g., from cold water loop 216) via piping 342 and may return thechilled fluid to waterside system 200 via piping 344. Valve 346 can bepositioned along piping 342 or piping 344 to control a flow rate of thechilled fluid through cooling coil 334. In some embodiments, coolingcoil 334 includes multiple stages of cooling coils that can beindependently activated and deactivated (e.g., by AHU controller 330, byBMS controller 366, etc.) to modulate an amount of cooling applied tosupply air 310.

Heating coil 336 may receive a heated fluid from waterside system 200(e.g., from hot water loop 214) via piping 348 and may return the heatedfluid to waterside system 200 via piping 350. Valve 352 can bepositioned along piping 348 or piping 350 to control a flow rate of theheated fluid through heating coil 336. In some embodiments, heating coil336 includes multiple stages of heating coils that can be independentlyactivated and deactivated (e.g., by AHU controller 330, by BMScontroller 366, etc.) to modulate an amount of heating applied to supplyair 310.

Each of valves 346 and 352 can be controlled by an actuator. Forexample, valve 346 can be controlled by actuator 354 and valve 352 canbe controlled by actuator 356. Actuators 354-356 may communicate withAHU controller 330 via communications links 358. Actuators 354-356 mayreceive control signals from AHU controller 330 and may provide feedbacksignals to controller 330. In some embodiments, AHU controller 330receives a measurement of the supply air temperature from a temperaturesensor 362 positioned in supply air duct 312 (e.g., downstream ofcooling coil 334 and/or heating coil 336). AHU controller 330 may alsoreceive a measurement of the temperature of building zone 306 from atemperature sensor 364 located in building zone 306.

In some embodiments, AHU controller 330 operates valves 346 and 352 viaactuators 354-356 to modulate an amount of heating or cooling providedto supply air 310 (e.g., to achieve a setpoint temperature for supplyair 310 or to maintain the temperature of supply air 310 within asetpoint temperature range). The positions of valves 346 and 352 affectthe amount of heating or cooling provided to supply air 310 by coolingcoil 334 or heating coil 336 and may correlate with the amount of energyconsumed to achieve a desired supply air temperature. AHU controller 330may control the temperature of supply air 310 and/or building zone 306by activating or deactivating coils 334-336, adjusting a speed of fan338, or a combination of both.

Still referring to FIG. 3, airside system 300 is shown to include abuilding management system (BMS) controller 366 and a client device 368.BMS controller 366 may include one or more computer systems (e.g.,servers, supervisory controllers, subsystem controllers, etc.) thatserve as system level controllers, application or data servers, headnodes, or master controllers for airside system 300, waterside system200, HVAC system 100, and/or other controllable systems that servebuilding 10. BMS controller 366 may communicate with multiple downstreambuilding systems or subsystems (e.g., HVAC system 100, a securitysystem, a lighting system, waterside system 200, etc.) via acommunications link 370 according to like or disparate protocols (e.g.,LON, BACnet, etc.). In various embodiments, AHU controller 330 and BMScontroller 366 can be separate (as shown in FIG. 3) or integrated. In anintegrated implementation, AHU controller 330 can be a software moduleconfigured for execution by a processor of BMS controller 366.

In some embodiments, AHU controller 330 receives information from BMScontroller 366 (e.g., commands, setpoints, operating boundaries, etc.)and provides information to BMS controller 366 (e.g., temperaturemeasurements, valve or actuator positions, operating statuses,diagnostics, etc.). For example, AHU controller 330 may provide BMScontroller 366 with temperature measurements from temperature sensors362-364, equipment on/off states, equipment operating capacities, and/orany other information that can be used by BMS controller 366 to monitoror control a variable state or condition within building zone 306.

Client device 368 may include one or more human-machine interfaces orclient interfaces (e.g., graphical user interfaces, reportinginterfaces, text-based computer interfaces, client-facing web services,web servers that provide pages to web clients, etc.) for controlling,viewing, or otherwise interacting with HVAC system 100, its subsystems,and/or devices. Client device 368 can be a computer workstation, aclient terminal, a remote or local interface, or any other type of userinterface device. Client device 368 can be a stationary terminal or amobile device. For example, client device 368 can be a desktop computer,a computer server with a user interface, a laptop computer, a tablet, asmartphone, a PDA, or any other type of mobile or nonmobile device.Client device 368 may communicate with BMS controller 366 and/or AHUcontroller 330 via communications link 372.

Referring now to FIG. 4, a block diagram of a building management system(BMS) 400 is shown, according to some embodiments. BMS 400 can beimplemented in building 10 to automatically monitor and control variousbuilding functions. BMS 400 is shown to include BMS controller 366 and aplurality of building subsystems 428. Building subsystems 428 are shownto include a building electrical subsystem 434, an informationcommunication technology (ICT) subsystem 436, a security subsystem 438,a HVAC subsystem 440, a lighting subsystem 442, a lift/escalatorssubsystem 432, and a fire safety subsystem 430. In various embodiments,building subsystems 428 can include fewer, additional, or alternativesubsystems. For example, building subsystems 428 may also oralternatively include a refrigeration subsystem, an advertising orsignage subsystem, a cooking subsystem, a vending subsystem, a printeror copy service subsystem, or any other type of building subsystem thatuses controllable equipment and/or sensors to monitor or controlbuilding 10. In some embodiments, building subsystems 428 includewaterside system 200 and/or airside system 300, as described withreference to FIGS. 2-3.

Each of building subsystems 428 may include any number of devices,controllers, and connections for completing its individual functions andcontrol activities. HVAC subsystem 440 may include many of the samecomponents as HVAC system 100, as described with reference to FIGS. 1-3.For example, HVAC subsystem 440 may include and number of chillers,heaters, handling units, economizers, field controllers, supervisorycontrollers, actuators, temperature sensors, and/or other devices forcontrolling the temperature, humidity, airflow, or other variableconditions within building 10. Lighting subsystem 442 may include anynumber of light fixtures, ballasts, lighting sensors, dimmers, or otherdevices configured to controllably adjust the amount of light providedto a building space. Security subsystem 438 may include occupancysensors, video surveillance cameras, digital video recorders, videoprocessing servers, intrusion detection devices, access control devicesand servers, or other security-related devices.

Still referring to FIG. 4, BMS controller 366 is shown to include acommunications interface 407 and a BMS interface 409. Interface 407 mayfacilitate communications between BMS controller 366 and externalapplications (e.g., monitoring and reporting applications 422,enterprise control applications 426, remote systems and applications444, applications residing on client devices 448, etc.) for allowinguser control, monitoring, and adjustment to BMS controller 366 and/orsubsystems 428. Interface 407 may also facilitate communications betweenBMS controller 366 and client devices 448. BMS interface 409 mayfacilitate communications between BMS controller 366 and buildingsubsystems 428 (e.g., HVAC, lighting security, lifts, powerdistribution, business, etc.)

Interfaces 407, 409 can be or include wired or wireless communicationsinterfaces (e.g., jacks, antennas, transmitters, receivers,transceivers, wire terminals, etc.) for conducting data communicationswith building subsystems 428 or other external systems or devices. Invarious embodiments, communications via interfaces 407, 409 can bedirect (e.g., local wired or wireless communications) or via acommunications network 446 (e.g., a WAN, the Internet, a cellularnetwork, etc.). For example, interfaces 407, 409 can include an Ethernetcard and port for sending and receiving data via an Ethernet-basedcommunications link or network. In another example, interfaces 407, 409can include a WiFi transceiver for communicating via a wirelesscommunications network. In another example, one or both of interfaces407, 409 may include cellular or mobile phone communicationstransceivers. In one embodiment, communications interface 407 is a powerline communications interface and BMS interface 409 is an Ethernetinterface. In other embodiments, both communications interface 407 andBMS interface 409 are Ethernet interfaces or are the same Ethernetinterface.

Still referring to FIG. 4, BMS controller 366 is shown to include aprocessing circuit 404 including a processor 406 and memory 408.Processing circuit 404 can be communicably connected to BMS interface409 and/or communications interface 407 such that processing circuit 404and the various components thereof can send and receive data viainterfaces 407, 409. Processor 406 can be implemented as a generalpurpose processor, an application specific integrated circuit (ASIC),one or more field programmable gate arrays (FPGAs), a group ofprocessing components, or other suitable electronic processingcomponents.

Memory 408 (e.g., memory, memory unit, storage device, etc.) may includeone or more devices (e.g., RAM, ROM, Flash memory, hard disk storage,etc.) for storing data and/or computer code for completing orfacilitating the various processes, layers and modules described in thepresent application. Memory 408 can be or include volatile memory ornon-volatile memory. Memory 408 may include database components, objectcode components, script components, or any other type of informationstructure for supporting the various activities and informationstructures described in the present application. According to someembodiments, memory 408 is communicably connected to processor 406 viaprocessing circuit 404 and includes computer code for executing (e.g.,by processing circuit 404 and/or processor 406) one or more processesdescribed herein.

In some embodiments, BMS controller 366 is implemented within a singlecomputer (e.g., one server, one housing, etc.). In various otherembodiments BMS controller 366 can be distributed across multipleservers or computers (e.g., that can exist in distributed locations).Further, while FIG. 4 shows applications 422 and 426 as existing outsideof BMS controller 366, in some embodiments, applications 422 and 426 canbe hosted within BMS controller 366 (e.g., within memory 408).

Still referring to FIG. 4, memory 408 is shown to include an enterpriseintegration layer 410, an automated measurement and validation (AM&V)layer 412, a demand response (DR) layer 414, a fault detection anddiagnostics (FDD) layer 416, an integrated control layer 418, and abuilding subsystem integration later 420. Layers 410-420 can beconfigured to receive inputs from building subsystems 428 and other datasources, determine optimal control actions for building subsystems 428based on the inputs, generate control signals based on the optimalcontrol actions, and provide the generated control signals to buildingsubsystems 428. The following paragraphs describe some of the generalfunctions performed by each of layers 410-420 in BMS 400.

Enterprise integration layer 410 can be configured to serve clients orlocal applications with information and services to support a variety ofenterprise-level applications. For example, enterprise controlapplications 426 can be configured to provide subsystem spanning controlto a graphical user interface (GUI) or to any number of enterprise-levelbusiness applications (e.g., accounting systems, user identificationsystems, etc.). Enterprise control applications 426 may also oralternatively be configured to provide configuration GUIs forconfiguring BMS controller 366. In yet other embodiments, enterprisecontrol applications 426 can work with layers 410-420 to optimizebuilding performance (e.g., efficiency, energy use, comfort, or safety)based on inputs received at interface 407 and/or BMS interface 409.

Building subsystem integration layer 420 can be configured to managecommunications between BMS controller 366 and building subsystems 428.For example, building subsystem integration layer 420 may receive sensordata and input signals from building subsystems 428 and provide outputdata and control signals to building subsystems 428. Building subsystemintegration layer 420 may also be configured to manage communicationsbetween building subsystems 428. Building subsystem integration layer420 translate communications (e.g., sensor data, input signals, outputsignals, etc.) across a plurality of multivendor/multi-protocol systems.

Demand response layer 414 can be configured to optimize resource usage(e.g., electricity use, natural gas use, water use, etc.) and/or themonetary cost of such resource usage in response to satisfy the demandof building 10. The optimization can be based on time-of-use prices,curtailment signals, energy availability, or other data received fromutility providers, distributed energy generation systems 424, fromenergy storage 427 (e.g., hot TES 242, cold TES 244, etc.), or fromother sources. Demand response layer 414 may receive inputs from otherlayers of BMS controller 366 (e.g., building subsystem integration layer420, integrated control layer 418, etc.). The inputs received from otherlayers may include environmental or sensor inputs such as temperature,carbon dioxide levels, relative humidity levels, air quality sensoroutputs, occupancy sensor outputs, room schedules, and the like. Theinputs may also include inputs such as electrical use (e.g., expressedin kWh), thermal load measurements, pricing information, projectedpricing, smoothed pricing, curtailment signals from utilities, and thelike.

According to some embodiments, demand response layer 414 includescontrol logic for responding to the data and signals it receives. Theseresponses can include communicating with the control algorithms inintegrated control layer 418, changing control strategies, changingsetpoints, or activating/deactivating building equipment or subsystemsin a controlled manner. Demand response layer 414 may also includecontrol logic configured to determine when to utilize stored energy. Forexample, demand response layer 414 may determine to begin using energyfrom energy storage 427 just prior to the beginning of a peak use hour.

In some embodiments, demand response layer 414 includes a control moduleconfigured to actively initiate control actions (e.g., automaticallychanging setpoints) which minimize energy costs based on one or moreinputs representative of or based on demand (e.g., price, a curtailmentsignal, a demand level, etc.). In some embodiments, demand responselayer 414 uses equipment models to determine an optimal set of controlactions. The equipment models may include, for example, thermodynamicmodels describing the inputs, outputs, and/or functions performed byvarious sets of building equipment. Equipment models may representcollections of building equipment (e.g., subplants, chiller arrays,etc.) or individual devices (e.g., individual chillers, heaters, pumps,etc.).

Demand response layer 414 may further include or draw upon one or moredemand response policy definitions (e.g., databases, XML files, etc.).The policy definitions can be edited or adjusted by a user (e.g., via agraphical user interface) so that the control actions initiated inresponse to demand inputs can be tailored for the user's application,desired comfort level, particular building equipment, or based on otherconcerns. For example, the demand response policy definitions canspecify which equipment can be turned on or off in response toparticular demand inputs, how long a system or piece of equipment shouldbe turned off, what setpoints can be changed, what the allowablesetpoint adjustment range is, how long to hold a high demand setpointbefore returning to a normally scheduled setpoint, how close to approachcapacity limits, which equipment modes to utilize, the energy transferrates (e.g., the maximum rate, an alarm rate, other rate boundaryinformation, etc.) into and out of energy storage devices (e.g., thermalstorage tanks, battery banks, etc.), and when to dispatch on-sitegeneration of energy (e.g., via fuel cells, a motor generator set,etc.).

Integrated control layer 418 can be configured to use the data input oroutput of building subsystem integration layer 420 and/or demandresponse later 414 to make control decisions. Due to the subsystemintegration provided by building subsystem integration layer 420,integrated control layer 418 can integrate control activities of thesubsystems 428 such that the subsystems 428 behave as a singleintegrated super system. In some embodiments, integrated control layer418 includes control logic that uses inputs and outputs from a pluralityof building subsystems to provide greater comfort and energy savingsrelative to the comfort and energy savings that separate subsystemscould provide alone. For example, integrated control layer 418 can beconfigured to use an input from a first subsystem to make anenergy-saving control decision for a second subsystem. Results of thesedecisions can be communicated back to building subsystem integrationlayer 420.

Integrated control layer 418 is shown to be logically below demandresponse layer 414. Integrated control layer 418 can be configured toenhance the effectiveness of demand response layer 414 by enablingbuilding subsystems 428 and their respective control loops to becontrolled in coordination with demand response layer 414. Thisconfiguration may reduce disruptive demand response behavior relative toconventional systems. For example, integrated control layer 418 can beconfigured to assure that a demand response-driven upward adjustment tothe setpoint for chilled water temperature (or another component thatdirectly or indirectly affects temperature) does not result in anincrease in fan energy (or other energy used to cool a space) that wouldresult in greater total building energy use than was saved at thechiller.

Integrated control layer 418 can be configured to provide feedback todemand response layer 414 so that demand response layer 414 checks thatconstraints (e.g., temperature, lighting levels, etc.) are properlymaintained even while demanded load shedding is in progress. Theconstraints may also include setpoint or sensed boundaries relating tosafety, equipment operating limits and performance, comfort, fire codes,electrical codes, energy codes, and the like. Integrated control layer418 is also logically below fault detection and diagnostics layer 416and automated measurement and validation layer 412. Integrated controllayer 418 can be configured to provide calculated inputs (e.g.,aggregations) to these higher levels based on outputs from more than onebuilding subsystem.

Automated measurement and validation (AM&V) layer 412 can be configuredto verify that control strategies commanded by integrated control layer418 or demand response layer 414 are working properly (e.g., using dataaggregated by AM&V layer 412, integrated control layer 418, buildingsubsystem integration layer 420, FDD layer 416, or otherwise). Thecalculations made by AM&V layer 412 can be based on building systemenergy models and/or equipment models for individual BMS devices orsubsystems. For example, AM&V layer 412 may compare a model-predictedoutput with an actual output from building subsystems 428 to determinean accuracy of the model.

Fault detection and diagnostics (FDD) layer 416 can be configured toprovide on-going fault detection for building subsystems 428, buildingsubsystem devices (i.e., building equipment), and control algorithmsused by demand response layer 414 and integrated control layer 418. FDDlayer 416 may receive data inputs from integrated control layer 418,directly from one or more building subsystems or devices, or fromanother data source. FDD layer 416 may automatically diagnose andrespond to detected faults. The responses to detected or diagnosedfaults may include providing an alert message to a user, a maintenancescheduling system, or a control algorithm configured to attempt torepair the fault or to work-around the fault.

FDD layer 416 can be configured to output a specific identification ofthe faulty component or cause of the fault (e.g., loose damper linkage)using detailed subsystem inputs available at building subsystemintegration layer 420. In other exemplary embodiments, FDD layer 416 isconfigured to provide “fault” events to integrated control layer 418which executes control strategies and policies in response to thereceived fault events. According to some embodiments, FDD layer 416 (ora policy executed by an integrated control engine or business rulesengine) may shut-down systems or direct control activities around faultydevices or systems to reduce energy waste, extend equipment life, orassure proper control response.

FDD layer 416 can be configured to store or access a variety ofdifferent system data stores (or data points for live data). FDD layer416 may use some content of the data stores to identify faults at theequipment level (e.g., specific chiller, specific AHU, specific terminalunit, etc.) and other content to identify faults at component orsubsystem levels. For example, building subsystems 428 may generatetemporal (i.e., time-series) data indicating the performance of BMS 400and the various components thereof. The data generated by buildingsubsystems 428 may include measured or calculated values that exhibitstatistical characteristics and provide information about how thecorresponding system or process (e.g., a temperature control process, aflow control process, etc.) is performing in terms of error from itssetpoint. These processes can be examined by FDD layer 416 to exposewhen the system begins to degrade in performance and alert a user torepair the fault before it becomes more severe.

Valve Assembly

Referring now to FIG. 5, a block diagram of an electronicpressure-independent control valve assembly 500 is shown, according tosome embodiments. Valve assembly 500 can be used in HVAC system 100,waterside system 200, airside system 300, or BMS 400, as described withreference to FIGS. 1-4. Valve assembly 500 is shown to include anactuator 502 coupled to a valve 504. For example, actuator 502 can be adamper actuator, a valve actuator, a fan actuator, a pump actuator, orany other type of actuator that can be used in an HVAC system or BMS. Invarious embodiments, actuator 502 can be a linear actuator (e.g., alinear proportional actuator), a non-linear actuator, a spring returnactuator, or a non-spring return actuator.

Valve 504 can be any type of control device configured to control anenvironmental parameter in an HVAC system, including a 2-way or 3-waytwo position electric motorized valve, a ball isolation valve, afloating point control valve, an adjustable flow control device, or amodulating control valve. In some embodiments, valve 504 may regulate aflow 520 of fluid through a conduit, pipe, tubular member, or tube(e.g., conduit 508) in a waterside system (e.g., waterside system 200,shown in FIG. 2). Conduit 508 may include upstream conduit sections 512and 514 and downstream conduit section 510.

In some embodiments, actuator 502 and valve 504 are located within acommon integrated device chassis or housing. In short, actuator 502 andvalve 504 may not be packaged as separate devices, but as a singledevice. Reducing the number of devices in an HVAC system may providenumerous advantages, most notably in time and cost savings during theinstallation process. Because it is not necessary to install actuator502 and valve 504 as separate devices and then make a connection betweenthem, technicians performing the installation may require lessspecialized training and fewer tools. Other advantages of a singledevice may include simplification of control and troubleshootingfunctions. However, in some embodiments, actuator 502 and valve 504 arepackaged as separate devices that can be communicably coupled via awired or a wireless connection.

Still referring to FIG. 5, a flow sensor assembly 506 is shown to becoupled to upstream conduit sections 512 and 514. Conduit 512 may be astraight connecting conduit having a length 522 that is installedbetween the flow sensor assembly 506 and the valve 504 to ensure properfunctioning of the flow sensor assembly 506. Flow sensor assembly 506can be configured to measure a flow rate or a velocity of fluid passingthrough conduit 508. Flow sensor assembly 506 can be any type of device(e.g., ultrasonic detector) configured to measure the flow rate orvelocity using any applicable flow sensing method.

Still referring to FIG. 5, flow sensor assembly 506 may be fixedlycoupled with a flow sensor processor 516. Flow sensor processor 516 canbe communicably coupled via a wired or a wireless connection to actuator502 and a measured volumetric flow and/or a velocity data 518 from flowrate sensor assembly 506 can be provided to actuator device 502. Flowsensor processor 516 can be implemented as a general purpose processor,an application specific integrated circuit (ASIC), one or more fieldprogrammable gate arrays (FPGAs), a group of processing components, orother suitable electronic processing components.

Turning now to FIG. 6, a block diagram of a signal filtering pressuredisturbance rejection valve assembly 600 is shown, according to someembodiments. Valve assembly 600 can be used in HVAC system 100,waterside system 200, airside system 300, or BMS 400, as described withreference to FIGS. 1-4. Valve assembly 600 may represent a more detailedversion of valve assembly 500. For example, valve assembly 600 is shownto include actuator 602, which can be identical or substantially similarto actuator 502 in valve assembly 500. Actuator 602 can be configured tooperate equipment 604. Equipment 604 may include any type of system ordevice that can be operated by an actuator (e.g., a valve, a damper). Inan exemplary embodiment, actuator 602 and equipment 604 (e.g., a valve)are packaged within a common integrated device chassis.

Actuator 602 is shown to include a processing circuit 606 communicablycoupled with a motor 628 (e.g., a rotary motor, a mechanical transducer,etc., or any other device configured to convert electrical energy tomechanical work). In some embodiments, motor 628 is a brushless DC(BLDC) motor. Processing circuit 606 is shown to include a processor608, memory 610, and a main actuator controller 632. Processor 608 canbe a general purpose or specific purpose processor, an applicationspecific integrated circuit (ASIC), one or more field programmable gatearrays (FPGAs), a group of processing components, or other suitableprocessing components. Processor 608 can be configured to executecomputer code or instructions stored in memory 610 or received fromother computer readable media (e.g., CDROM, network storage, a remoteserver, etc.).

Memory 610 may include one or more devices (e.g., memory units, memorydevices, storage devices, etc.) for storing data and/or computer codefor completing and/or facilitating the various processes described inthe present disclosure. Memory 610 may include random access memory(RAM), read-only memory (ROM), hard drive storage, temporary storage,non-volatile memory, flash memory, optical memory, or any other suitablememory for storing software objects and/or computer instructions. Memory610 may include database components, object code components, scriptcomponents, or any other type of information structure for supportingthe various activities and information structures described in thepresent disclosure. Memory 610 can be communicably connected toprocessor 608 via processing circuit 606 and may include computer codefor executing (e.g., by processor 608) one or more processes describedherein. When processor 608 executes instructions stored in memory 610,processor 608 generally configures actuator 602 (and more particularlyprocessing circuit 606) to complete such activities.

Main actuator controller 632 may be configured to receive externalcontrol data 616 (e.g., position setpoints, speed setpoints, etc.) fromcommunications circuit 612, position signals 624 from position sensors622, and flow signals 640 from one or more flow sensors 638. Mainactuator controller 632 may be configured to determine the position ofmotor 628 and/or drive device 630 based on position signals 624. In someembodiments, main actuator controller 632 receives data from additionalsources. For example, motor current sensor 618 may be configured tomeasure the electric current provided to motor 628. Motor current sensor618 may generate a feedback signal indicating the motor current 620 andmay provide this signal to main actuator controller 632 withinprocessing circuit 608.

System fluctuations (e.g., pressure fluctuations) may result in highvariance in the flow signals 640 received from the flow sensors 638 anderratic control of the valve member position. Various techniques maytherefore be utilized to minimize variance in ultrasonic measurements.Flow signal filtering circuit 636 can be configured to implement variousstatistical filtering techniques (e.g. low pass filtering, Kalmanfiltering, etc.). In some embodiments, Kalman filters may be implementedto estimate a joint probability distribution for a flow sensormeasurement at each time step. In other embodiments, low pass filteringtechniques may be utilized to remove high frequency noise. The cutofffrequency for the filter may be based on various valve characteristics(e.g., valve size, type of valve). Because higher flow velocities leadto noisier measurements, any physical valve characteristic that altersthe flow velocity through the valve may be considered in choosing acutoff frequency for the filter. Filters may be enabled or disabled whenthe flow rate through the valve is changing rapidly. In still furtherembodiments, sensor fusion techniques to combine measurements frommultiple ultrasonic sensors may be utilized. Each of the mathematicaltechniques described above may be utilized in isolation or incombination with one or more other mathematical techniques.

Still referring to FIG. 6, processing circuit 608 may be configured tooutput a pulse width modulated (PWM) DC motor command 634 to control thespeed of the motor. Motor 628 may be configured to receive a three-phasePWM voltage output (e.g., phase A, phase B, phase C) from motor driveinverter 626. The duty cycle of the PWM voltage output may define therotational speed of motor 628 and may be determined by processingcircuit 606 (e.g., a microcontroller). Processing circuit 606 mayincrease the duty cycle of the PWM voltage output to increase the speedof motor 628 and may decrease the duty cycle of the PWM voltage outputto decrease the speed of motor 628.

Motor 628 may be coupled to drive device 630. Drive device 630 may be adrive mechanism, a hub, or other device configured to drive oreffectuate movement of a HVAC system component (e.g., equipment 604).For example, drive device may be configured to receive a shaft of adamper, a valve, or any other movable HVAC system component in order todrive (e.g., rotate) the shaft. In some embodiments, actuator 602includes a coupling device configured to aid in coupling drive device630 to the movable HVAC system component. For example, the couplingdevice may facilitate attaching drive device 630 to a valve or dampershaft.

Position sensors 622 may include Hall effect sensors, potentiometers,optical sensors, or other types of sensors configured to measure therotational position of the motor 628 and/or drive device 630. Positionsensors 622 may provide position signals 624 to processing circuit 606.Main actuator controller 632 may use position signals 624 to determinewhether to operate the motor 628. For example, main actuator controller632 may compare the current position of drive device 630 with a positionsetpoint received via external data input 616 and may operate the motor628 to achieve the position setpoint.

Actuator 602 is further shown to include a communications circuit 612.Communications circuit 612 may be a wired or wireless communicationslink and may use any of a variety of disparate communications protocols(e.g., BACnet, LON, WiFi, Bluetooth, NFC, TCP/IP, etc.). In someembodiments, communications circuit 612 is an integrated circuit, chip,or microcontroller unit (MCU) configured to bridge communicationsactuator 602 and external systems or devices. In some embodiments,communications circuit 612 is the Johnson Controls BACnet on a Chip(JBOC) product. For example, communications circuit 612 can be apre-certified BACnet communication module capable of communicating on abuilding automation and controls network (BACnet) using a master/slavetoken passing (MSTP) protocol. Communications circuit 612 can be addedto any existing product to enable BACnet communication with minimalsoftware and hardware design effort. In other words, communicationscircuit 612 provides a BACnet interface for the pressure disturbancerejection valve assembly 600. Further details regarding the JBOC productare disclosed in U.S. patent application Ser. No. 15/207,431 filed Jul.11, 2016, the entire disclosure of which is incorporated by referenceherein.

Communications circuit 612 may also be configured to support datacommunications within actuator 602. In some embodiments, communicationscircuit 612 may receive internal actuator data 614 from main actuatorcontroller 632. For example, internal actuator data 614 may include thesensed motor current 620, a measured or calculated motor torque, theactuator position or speed, configuration parameters, end stoplocations, stroke length parameters, commissioning data, equipment modeldata, firmware versions, software versions, time series data, acumulative number of stop/start commands, a total distance traveled, anamount of time required to open/close equipment 604 (e.g., a valve), orany other type of data used or stored internally within actuator 602. Insome embodiments, communications circuit 612 may transmit external data616 to main actuator controller 632. External data 616 may include, forexample, position setpoints, speed setpoints, control signals,configuration parameters, end stop locations, stroke length parameters,commissioning data, equipment model data, actuator firmware, actuatorsoftware, or any other type of data which can be used by actuator 602 tooperate the motor 628 and/or drive device 630.

In some embodiments, external data 616 is a DC voltage control signal.Actuator 602 can be a linear proportional actuator configured to controlthe position of drive device 630 according to the value of the DCvoltage received. For example, a minimum input voltage (e.g., 0.0 VDC)may correspond to a minimum rotational position of drive device 630(e.g., 0 degrees, −5 degrees, etc.), whereas a maximum input voltage(e.g., 10.0 VDC) may correspond to a maximum rotational position ofdrive device 630 (e.g., 90 degrees, 95 degrees, etc.). Input voltagesbetween the minimum and maximum input voltages may cause actuator 602 tomove drive device 630 into an intermediate position between the minimumrotational position and the maximum rotational position. In otherembodiments, actuator 602 can be a non-linear actuator or may usedifferent input voltage ranges or a different type of input controlsignal (e.g., AC voltage or current) to control the position and/orrotational speed of drive device 630.

In some embodiments, external data 616 is an AC voltage control signal.Communications circuit 612 may be configured to transmit an AC voltagesignal having a standard power line voltage (e.g., 120 VAC or 230 VAC at50/60 Hz). The frequency of the voltage signal can be modulated (e.g.,by main actuator controller 632) to adjust the rotational positionand/or speed of drive device 630. In some embodiments, actuator 602 usesthe voltage signal to power various components of actuator 602. Actuator602 may use the AC voltage signal received via communications circuit612 as a control signal, a source of electric power, or both. In someembodiments, the voltage signal is received from a power supply linethat provides actuator 602 with an AC voltage having a constant orsubstantially constant frequency (e.g., 120 VAC or 230 VAC at 50 Hz or60 Hz). Communications circuit 612 may include one or more dataconnections (separate from the power supply line) through which actuator602 receives control signals from a controller or another actuator(e.g., 0-10 VDC control signals).

Feedback Control System

Turning now to FIG. 7, a block diagram of an actuator device 702 withina feedback control system 700 is shown. In some embodiments, thefeedback control system 700 is a cascaded feedback control system. In acascaded control system, a primary controller (e.g., controller 704)generates a control signal that serves as the setpoint for a secondarycontroller (e.g., flow/velocity feedback controller 736). In someembodiments, the control path including the control signal generated bythe primary controller may be referred to as an “outer loop,” while thecontrol path including the secondary controller may be referred to as an“inner loop.” In some embodiments, cascaded control system 700 is acomponent or subsystem of HVAC system 100, waterside system 200, airsidesystem 300, or BMS 400, as described with reference to FIGS. 1-4.

Cascaded control system 700 may include, among other components,actuator device 702, controller 704, building zone 706, zone temperaturecontroller 724, and valve 746. In some embodiments, controller 704 is aprimary controller for the components of an HVAC system (e.g., HVACsystem 100) within the outer control loop of cascaded control system700. In other embodiments, controller 704 is a thermostat or a BMScontroller (e.g., for BMS 400). In still further embodiments, controller704 is a user device configured to run a building management application(e.g., a mobile phone, a tablet, a laptop). Controller 704 may receivedata from temperature sensor 708. Temperature sensor 708 may be any typeof sensor or device configured to measure an environmental condition(e.g., temperature) of a building zone 706. Building zone 706 may be anysubsection of a building (e.g., a room, a block of rooms, and a floor).

Controller 704 is shown to include a digital filter 712, a wirelesscommunications interface 718, and a comparator 720. Measured zonetemperature data 710 from temperature sensor 708 may be received as aninput signal to digital filter 712. Digital filter 712 may be configuredto convert the measured zone temperature data 710 into a measured zonetemperature feedback signal 714 that may be provided as an input tocomparator 720. In some embodiments, digital filter 712 is a first orderlow pass filter. In other embodiments, digital filter 712 may be a lowpass filter of a different order or a different type of filter.

Controller 704 is further shown to include wireless communicationsinterface 718. In some embodiments, wireless communications interface718 may communicate data from controller 704 to communications interface752 of actuator device 702. In other embodiments, communicationsinterfaces 718 and 752 may communicate with other external systems ordevices. Communications via interface 718 may be direct (e.g., localwireless communications) or via a communications network (e.g., a WAN,the Internet, a cellular network). For example, interfaces 718 and 752may include a Wi-Fi transceiver for communicating via wirelesscommunications network. In another example, one or both interfaces 718and 752 may include cellular or mobile phone communicationstransceivers. In some embodiments, multiple controllers and smartactuator devices may communicate using a mesh topology. In otherembodiments, communications interfaces 718 and 752 may be configured totransmit smart actuator device data (e.g., a fault status, an actuatorand/or valve position) to an external network. In still furtherembodiments, communications interfaces 718 and 752 are connected via awired, rather than wireless, network.

Comparator 720 may be configured to compare the measured zonetemperature feedback signal 714 output from digital filter 712 with azone temperature setpoint value 716. Comparator 720 may then output atemperature error signal 722 that is received by zone temperaturecontroller 724. Comparator 720 may be a discrete electronics part orimplemented as part of controller 704. If comparator 720 determines thatthe zone temperature feedback signal 714 is higher than the zonetemperature setpoint value 716 (i.e., building zone 706 is hotter thanthe setpoint value), zone temperature controller 724 may output acontrol signal that causes actuator device 702 to modify the flow ratethrough water coil 750 such that cooling to building zone 706 isincreased. If comparator 720 determines that the zone temperaturefeedback signal 714 is lower than the zone temperature setpoint value716 (i.e., building zone 706 is cooler than the setpoint value), zonetemperature controller 724 may output a control signal that causesactuator device 702 to modify the flow rate through water coil 750 suchthat heating to building zone 706 is increased.

In various embodiments, zone temperature controller 724 is a patternrecognition adaptive controller (PRAC), a model recognition adaptivecontroller (MRAC), or another type of tuning or adaptive feedbackcontroller. Adaptive control is a control method in which a controllermay adapt to a controlled system with associated parameters which vary,or are initially uncertain. In some embodiments, zone temperaturecontroller 724 is similar or identical to the adaptive feedbackcontroller described in U.S. Pat. No. 8,825,185, granted on Sep. 2,2014, the entirety of which is herein incorporated by reference.

Still referring to FIG. 7, actuator device 702 is shown to include aflow/velocity span block 726, a comparator 730, a flow/velocity feedbackcontroller 736, a valve actuator 740, and a communications interface752. Zone temperature error 722 output from comparator 720 may betransmitted to actuator 702 via zone temperature controller 724.Flow/velocity span block 726 may be configured to enforce allowablemaximum and minimum flow range limits on the received zone temperatureerror 722. For example, a technician installing the components ofcascaded control system 700 or an administrator of HVAC system 100 mayinput a maximum and/or a minimum flow range limit for the flow/velocityspan block 726. In some embodiments, the flow range limits aretransmitted via mobile device (e.g., a smart phone, a table) and arereceived via communications interface 752 of actuator device 702. Inother embodiments, the flow range limits are transmitted to interface752 via wired network.

Comparator 730 may compare the flow rate/velocity setpoint 728 outputreceived from flow/velocity span block 726 to measured flowrate/velocity data. Measured flow rate velocity data may be receivedfrom flow rate sensor 748. Comparator 730 may be a discrete electronicspart or implemented as part of flow/velocity feedback controller 736. Insome embodiments, comparator 730 may output a flow rate/velocity errorsignal 734 to flow/velocity feedback controller 736. For example, ifcomparator 730 determines that flow rate/velocity setpoint 728 is higherthan measured flow rate/velocity 742, comparator 730 may generate a flowrate/velocity error signal 734 that causes flow/velocity feedbackcontroller 736 to operate valve actuator 740 to increase the flowrate/velocity through valve 746. Conversely, if comparator 730determines that flow rate/velocity setpoint 728 is lower than measuredflow rate/velocity 742, comparator 730 may generate a flow rate/velocityerror signal 734 that causes flow/velocity feedback controller 736 tooperate valve actuator 740 to decrease the flow rate/velocity throughvalve 746.

Flow/velocity feedback controller 736 is configured to receive a flowrate/velocity error signal 734 from comparator 730 and to output acommand signal to valve actuator 740 to drive the error signal to zero(i.e., to operate valve actuator 740 such that the measured flowrate/velocity 742 is equal to the flow rate/velocity setpoint 728).Similar to zone temperature controller 724, in various embodiments,flow/velocity feedback controller 736 is a proportional variabledeadband controller (PVDC), a pattern recognition adaptive controller(PRAC), a model recognition adaptive controller (MRAC), or another typeof tuning or adaptive feedback controller. In other embodiments,flow/velocity feedback controller 736 operates using state machine orproportional-integral-derivative (PID) logic. In some embodiments,flow/velocity feedback controller 736 is identical or substantiallysimilar to the main actuator controller 632 as described with referenceto FIG. 6.

Flow/velocity feedback controller 736 may be configured to output anactuator control signal (e.g., a DC signal, an AC signal) to valveactuator 740. In some embodiments, valve actuator 740 is identical orsubstantially similar to actuators 502 and 602 as described withreference to FIGS. 5 and 6. For example, valve actuator 740 may be alinear actuator (e.g., a linear proportional actuator), a non-linearactuator, a spring return actuator, or a non-spring return actuator.Valve actuator 740 may include a drive device coupled to valve 746 andconfigured to rotate a shaft of valve 746. In some embodiments, valve746 is identical or substantially similar to valves 504 and 604 asdescribed with reference to FIGS. 5 and 6. For example, in variousembodiments, valve 746 may be a 2-way or 3-way two position electricmotorized valve, a ball isolation valve, a floating point control valve,an adjustable flow control device, or a modulating control valve.

Still referring to FIG. 7, cascaded flow rate system is further shown toinclude a flow rate sensor 748. In some embodiments, flow rate sensor748 is identical or substantially similar to the flow rate sensors 506and 638 as described with reference to FIGS. 5 and 6. Flow rate sensor748 may be disposed downstream of valve 746 to measure the flow rateand/or velocity of fluid exiting valve 746. In other embodiments, flowrate sensor 748 may be disposed upstream of valve 746. In someembodiments, flow rate sensor 748 is configured to have high sensitivityto changes in flow rate or velocity and, at the same time, to rejectpressure fluctuations within the system. In further embodiments,cascaded control systems may be configured to reject fluctuations insystem characteristics other than pressure. For example, thesecharacteristics may include inlet water temperature, inlet airtemperature, and airside mass flow. Once collected, measured flow rateand/or velocity data 742 from flow rate sensor 748 may be provided tocomparator 730 of actuator device 702.

Fluid that passes through valve 746 may flow through water coil 750. Insome embodiments, valve 746 is used to modulate an amount of heating orcooling provided to the supply air for building zone 706. In variousembodiments, water coil 750 may be used to achieve zone setpointtemperature 716 for the supply air of building zone 706 or to maintainthe temperature of supply air for building zone 706 within a setpointtemperature range. The position of valve 746 may affect the amount ofheating or cooling provided to supply air via water coil 750 and maycorrelate with the amount of energy consumed to achieve a desired supplyair temperature.

Reduced Length Ultrasonic Flow Sensor Assembly

Referring now to FIG. 8, a schematic diagram depicting the generaloperation of an ultrasonic flow sensor assembly 800 is shown, accordingto some embodiments. Ultrasonic flow sensor assembly 800 is shown toinclude ultrasonic transducers 804 and 810 (e.g.reversible-electric-ultrasonic-microphone-speakers), fixed to (e.g.,fixedly coupled with) a pipe 814 with a nominal diameter 828, D. Theultrasonic transducers 804 and 810 are attached to (e.g., operativelyand/or electrically coupled with) communication lines (e.g. networkinterfaces) 802 and 812 respectively. In some embodiments, communicationlines 802 and 812 can be wireless. In other embodiments, communicationlines 802 and 812 can be wired. In some embodiments, ultrasonictransducers 804 and 810 are disc-shaped members (e.g., flat disc-shapedmembers).

In some embodiments, ultrasonic flow sensor assembly 800 includes astructural member, a housing member, a rigid member, an enclosure, etc.,shown as structural member 805. Structural member 805 may enclose orprovide structural support for ultrasonic transducers 804 and 810. Insome embodiments, ultrasonic transducers 804 and 810 are fixedly coupledwith structural member 805 such that structural member 805, andultrasonic transducers 804 and 810 form an assembly. In someembodiments, the assembly may be removably fixedly coupled with theconduit 814 (e.g., fastened, riveted, adhered, etc.). In someembodiments, structural member 805 is a rigid member along whichultrasonic transducers 804 and 810 are fixedly coupled so that adistance between ultrasonic transducers 804 and 810 is fixed.

Ultrasonic transducers 804 and 810 are located a fixed distance 826, L,from each other. This distance 826 can be directly proportional to thediameter 828 of the conduit 814. In some embodiments, distance 826 issubstantially equal to twice the diameter 828 of the conduit 814.Ultrasonic transducers 804 and 810 may contain an electronic circuitthat is configured to alternately send an ultrasonic signal (e.g.ultrasonic sound wave) which travels along an ultrasonic wave path 806in the direction 822 or 824. In some embodiments, ultrasonic transducer804 is upstream relative to ultrasonic transducer 810. Acousticreflectors 808 and 818 reflect the ultrasonic signals along ultrasonicwave path 806. For example, ultrasonic transducer 810 sends anultrasonic signal to ultrasonic transducer 804 upstream that travelsalong ultrasonic wave path 806 in direction 822. Ultrasonic transducer804 detects the ultrasonic signal generated by ultrasonic transducer 810(downstream). In some embodiments, ultrasonic transducers 804 and 810are configured to convert ultrasonic waves to voltage or current, orvice versa. Then, the electronic circuit measures the elapsed time fromthe instant the ultrasonic signal is generated from ultrasonictransducer 810 to the instant ultrasonic transducer 804 receives theultrasonic signal. This is called transit or travel time also referredto as t_(transit) which may be t_(transit,up) (e.g., transit timeupstream) or t_(transit,down) (e.g., transit time downstream). Theelectronic circuit then reverses the operation and sends anotherultrasonic signal this time to ultrasonic transducer 810 in direction824 and measures the transit time t_(transit) from ultrasonic transducer804. Since the acoustic signals travel at the speed of sound in themedium, the time to travel in a direction of a flow 820 is less than thetime to travel in the opposite direction of flow 820. The difference intravel time is proportional to a fluid speed (e.g. measured in metersper second (m/s)). Knowing the diameter 828 of pipe 814, a volumetricflow rate (e.g. measured in meters cubed per second (m³/s)) of the fluidcan be calculated. In some embodiments, the electronic operatesultrasonic transducers 804 and 810 to perform the operations describedherein to detect or obtain the volumetric flow rate of the fluid throughpipe 814.

In some embodiments, transducers 804 and 810 may not require acousticreflectors 808 and 818. Discarding acoustic reflectors 808 and 818 in anHVAC system may provide advantages, most notably to provide moreeffective flow rate readings when a large diameter 828 pipe 814 is used.However, in some embodiments, transducers 804 and 810 require acousticreflectors 808 and 818, most notably to provide more effective flow ratereadings when a small diameter 828 pipe 814 is used. Variousconfigurations of reduced length ultrasonic flow sensor assemblies aredescribed in further detail below with reference to FIGS. 11 and 12.

Referring now to FIG. 9, a schematic diagram of a downstream arrangementof a valve-coupled ultrasonic electronic pressure-independent controlassembly 900 is shown, according to some embodiments. Valve-coupledcontrol assembly 900 is shown to include an actuator 902 coupled to avalve 904. Actuator 902 may include a motor 912 coupled to a drivedevice 914. In some embodiments, actuator 902, actuator 702, and/oractuator 602 are the same as or similar to each other. For exampleactuator 902 can include any of the features, functionality,configuration, etc., of actuator 702 and/or actuator 602, and viceversa. Drive device 914 is driven by motor 912 and configured to rotatea valve shaft 916 attached to a valve stem 930. Valve stem 930consequently drives a valve member 918 to a position (i.e., actuatorsetpoint) resulting in regulation of a flow 928 of a fluid. Actuator 902is also shown to include an actuator processing circuit 908 communicablycoupled to motor 912 and a flow sensor processing circuit 910. Actuatorprocessing circuit 908 can be communicably coupled to the flow sensorprocessing circuit 910 and the various components thereof can send andreceive data (e.g. flow rate data, flow data, flow measurement data) viaa wired or wireless network interface. In some embodiments, the actuatorprocessing circuit 908 and flow sensing processing circuit 910 may bothuse communication mechanisms of a variety of disparate communicationsprotocols (e.g., BACnet, LON, WiFi, Bluetooth, NFC, TCP/IP, etc.).

In some embodiments, the flow sensing processing circuit 910 can providefiltered measurements (e.g. flow rate) to the actuator processingcircuit 908 using statistical filtering techniques (e.g. low passfiltering, Kalman filtering, etc.). Various statistical filteringtechniques can be utilized to minimize variance in data measurements, asdescribed above with reference to FIG. 6. Calculated data (e.g.,filtered flow measurements) in addition to received data (e.g., flowrate setpoints) can be used to determine actuator setpoints, asdescribed with reference to FIG. 6.

For example, flow sensing processing circuit 910 may be configured toreceive sensor data from ultrasonic transducers 924 and 926 and outputfiltered measurements (e.g., of the flow rate) to the actuatorprocessing circuit 908 using a Kalman filter. In some embodiments, flowsensing processing circuit 910 is configured to use any of the filteringtechniques described in greater detail with reference to U.S.application Ser. No. 13/756,229, filed Jan. 31, 2013, now U.S. Pat. No.9,568,204, the entire disclosure of which is incorporated by referenceherein. For example, flow sensing processing circuit 910 can include aKalman filter having a matrix Q (e.g., a process noise covariancematrix) that can be adaptively reset or adjusted. In some embodiments,flow sensing processing circuit 910 is configured to perform process 500shown in FIG. 5 of U.S. Pat. No. 9,568,204 using sensor data or flowmeasurements received from any of the ultrasonic transducers describedherein to filter the sensor data or the flow measurements.

Still referring to FIG. 9, valve-coupled control assembly 900 is furthershown to include flow sensor assembly 906 directly coupled to valve 904without requiring a length of conduit situated between the flow sensor906 and the valve 904. Eliminating the requirement of conduit (e.g.straight pipe) between flow sensor 906 and valve 904 may providenumerous advantages, most notably in reducing the overall size andnumber of parts in valve assembly 900.

The operation of flow sensor assembly 906 can be identical orsubstantially similar to the ultrasonic flow sensor 800, as described inreference to FIG. 8. For example, flow sensor 906 may include one ormore, among other components, acoustic reflectors (mirrors), ultrasonictransducers, communication lines, and pipes. In some embodiments,communication lines (e.g. network interface) 920 and 922 connectingultrasonic transducers 924 and 926 that use acoustic reflectors 934 and936 to flow sensor processing circuit 910 can be wireless. In otherembodiments, communication lines 920 and 922 connecting ultrasonictransducers 924 and 926 to flow sensor processing circuit 910 can bewired. Various configurations of flow sensor assembly 906 are describedin further detail below with reference to FIG. 11 and FIG. 12.

Turning now to FIG. 10, a schematic diagram of an upstream arrangementof a valve-coupled ultrasonic electronic pressure-independent controlassembly 1000 is shown, according to some embodiments. The valve-coupledcontrol assembly 1000 can be substantially similar to the valve-coupledcontrol assembly 900, as described in reference to FIG. 9, and mayinclude any of the components, functionality, configuration, etc., ofthe valve-coupled control assembly 900. For example, valve-coupledcontrol assembly 1000 may include, among other components, actuator 902,valve 904, and flow sensor assembly 906. Valve-coupled control assembly1000 may include at modification in reference to the location of flowsensor assembly 906. Flow sensor assembly 906 can be located upstream inreference to valve 904, while valve-coupled control assembly 900 mayhave flow sensor assembly 906 located downstream in reference to valve904. In some embodiments, locating flow sensor assembly 906 upstream (asshown in FIG. 10) results in more reliable flow measurements due to alack of flow turbulence. In some embodiments, placing the flow sensorassembly 906 downstream of valve 904 results in a known disturbanceupstream of the flow sensor assembly 906 and facilitates reducing orremoving the risk of unknown flow dynamics. In some embodiments,positioning the flow sensor assembly 906 downstream of valve 904facilitates reducing an overall installation length since no extra pipediameters upstream of sensor assembly 906 are required. However, due tothe turbulence generated by the valve 904, it may be desirable to placesensor assembly 906 upstream od valve 904.

Referring now to FIG. 11, a schematic diagram of a mirroredconfiguration of a standalone ultrasonic flow sensor assembly 1100 isshown. In some embodiments, ultrasonic flow sensor assembly 1100 isshown to include ultrasonic transducers 1114 and 1116. Ultrasonictransducers 1114 and 1116 can be identical or substantially similar toultrasonic transducers 804 and 812, as described with reference to FIG.8. Ultrasonic flow sensor assembly 1100 is further shown to include afixed pipe 1104, an ultrasonic wave path 1110, and a flow 1118. In someembodiments, ultrasonic wave path 1110 and fluid flow 1118 is identicalor substantially similar to ultrasonic wave path 806 and flow 820, asdescribed with reference to FIG. 8.

Ultrasonic flow sensor assembly 1100 also includes acoustic reflectors(i.e., mirrors) 1102 and 1106. Simply, acoustic reflectors 1102 and 1106reflect the ultrasonic signals along ultrasonic wave path 1110. Acousticreflectors 1102 and 1106 are also shown to be fixed regardless of orindependent of pipe diameter (e.g. diameter 828) such that a distance1120, between acoustic reflector 1102 and 1106 is constant. In someembodiments, a minimum distance between acoustic reflectors 1102 and1106 (e.g., a minimum value of distance 1120) is 1 diameter of thesensor assembly (e.g., the ultrasonic transducers 1114 and 1116 aremounted directly next to each other). In some embodiments, a housing ofthe ultrasonic transducers 1114 and 1116 results in a mechanicalrestriction. In some embodiments, distance 1120 is a function of thesensor diameter 815 and/or a diameter of the conduit (e.g., diameter828). For example, distance 1120 may be substantially equal to 1.25×Dwhere D is a diameter 815 of any of the ultrasonic transducers (e.g.,ultrasonic transducers 804, 810, as shown in FIG. 8, transducers 924 or926 as shown in FIGS. 9 and 10, transducers 1114 and 1116 as shown inFIG. 11, or ultrasonic transducers 1202 and 1204 as shown in FIG. 12).Fixed distance 1120 between acoustic reflectors 1102 and 1106 allowsultrasonic flow sensor 1100 to satisfy applications with an overallshorter sensor body.

Referring back to FIG. 8, the distance 826 between ultrasonictransducers 804 and 810 is necessary to control a signal-to-noise-ratio(“S/N”), and will fluctuate depending on diameter 828 of the flow sensorassembly 800. The overall shorter sensor assembly of FIG. 11 can beaccomplished by using statistical filtering techniques, as described inreference to FIG. 6. In some embodiments, the use of statisticalfiltering techniques can reduce the distance between transducers 1114and 1116 up to 50% when compared to a flow sensor assembly that does notutilize statistical filtering techniques. Specifically, utilizingstatistical filtering techniques may facilitate reducing the length of a“normal length” flow sensor (e.g., a flow sensor that does not usestatistical filtering techniques) or current manufacturing practice.

Turning now to FIG. 12, a schematic diagram of a mirrorlessconfiguration of a standalone ultrasonic flow sensor assembly 1200 isshown, according to some embodiments. Ultrasonic flow sensor assembly1200 is shown to include ultrasonic transducers 1202 and 1204 fixed to apipe 1208. In some embodiments, ultrasonic transducers 1202 and 1204 canbe positioned opposed of each other (i.e., a flow of fluid 1212 passesbetween the transducers 1202 and 1204). Ultrasonic transducers 1202 and1204 each contain an electronic circuit that is configured toalternately send an ultrasonic signal (e.g. ultrasonic sound wave) whichtravels along an ultrasonic wave path 1206 at an angle 1210 respect tothe flow 1212. In some embodiments, angle 1210 has a value of 45degrees. In some embodiments, angle 1210 is any value between 30 and 60degrees. For example, ultrasonic transducer 1202 sends an ultrasonicsignal to ultrasonic transducer 1204 upstream that travels alongultrasonic wave path 1206 at the angle 1210, rather than ultrasonic wavepath 806 that travels in a perpendicular and parallel path with respectto flow 820, as described with reference to FIG. 8. Ultrasonictransducer 1204 detects the ultrasonic signal generated by ultrasonictransducer 1202 (downstream). An electronic circuit (e.g., flow sensorprocessing circuit 910) measures the elapsed time from the instant theultrasonic signal is generated from ultrasonic transducer 1202 to theinstant ultrasonic transducer 1204 receives the ultrasonic signal. Theelectronic circuit then reverses the operation and sends anotherultrasonic signal this time to ultrasonic transducer 1204 at the angle1210 and measures a transit time from ultrasonic transducer 1204. Insome embodiments, the mirrorless configuration of the standaloneultrasonic flow sensor assembly 1200 is used for pipes with largerdiameters (e.g., with inner diameters that are 4 inches or greater).

Turning now to FIG. 13, a flow diagram of a process 1300 for operating avalve-coupled ultrasonic electronic pressure-independent controlassembly, according to an exemplary embodiment. In some embodiments,process 1300 may be performed by control assembly 900 or controlassembly 1000, described above with reference to FIGS. 9-10. In otherembodiments, process 1300 may be performed by the flow signal filteringcircuit 636 of actuator 602, described above with reference to FIG. 6.For the purposes of simplicity, process 1300 will be describedexclusively with reference to control assembly 900. Process 1300 isshown to commence with step 1302, in which one or more ultrasonictransducers (e.g. transducers 924 and 926) collect flow rate data. Moreparticularly, the ultrasonic transducers 924 and 926 collect the flowrate data by sending one or more ultrasonic signals along an ultrasonicwave path 932.

At step 1304, the flow sensor assembly 906 communicates the flow ratedata to an actuator 902 (and more particularly to the flow sensorprocessing circuit 910). In some embodiments, the unfiltered flow ratedata may be designated as “raw” flow rate data. In some embodiments, theflow sensor processing circuit 910 receives the flow rate data through awireless connection from the flow sensor assembly 906. In otherembodiments, flow sensor processing circuit 910 receives the flow ratedata through a wired connection from the flow sensor assembly 906.

Process 1300 continues with step 1306, in which the flow sensorprocessing circuit 910 performs statistical filtering techniques (e.g.low pass filtering, Kalman filtering) on the flow rate data. In someembodiments, one or more high variance signals in one or more flowmeasurements can be observed. High variance signals can be addressed byperforming statistical filtering techniques on the flow measurements.For example, even when there are high-variance signals, performingstatistical filtering techniques may result in accurate and consistentflow measurements. Further details of statistical filtering techniquesare included above and with reference to FIG. 6 (e.g., in paragraph[0097]).

At step 1308, after performing statistical filtering techniques theactuator processing circuit 908 may determine an actuator positionsetpoint. In some embodiments, the actuator position setpoint can bedetermined in a process identical or substantially similar to theprocess performed by actuator processing circuit 908 as described withreference to FIG. 9. For example, in an exemplary embodiment, theactuator processing circuit 908 determines the actuator setpoint using aPVDC control technique. In other embodiments, a different type offeedback control may be utilized.

Process 1300 continues with step 1310, in which the actuator setpoint isused by actuator 902 to engage motor 912. In some embodiments, the drivedevice 914 can be configured to be driven by the motor 912 and coupledto the valve 904 for driving valve stem 930 within a range of positions.For example, actuator 902 receives a new setpoint in which a chain ofsequences follows. The new setpoint is communicated to motor 912 thatoperates drive device 914 so that it can rotate valve shaft 916 which isattached to valve stem 930. The valve stem 930 operates the valve member918 within a range of positions, subsequently regulating the flow 928 ofthe fluid through the valve body 904. In some embodiments, valve member918 may regulate the flow of the fluid through a conduit, pipe, duct, ortube.

Turning now to FIG. 14, a flow diagram of a process 1400 for filteringflow measurements is shown, according to an exemplary embodiment. Insome embodiments, process 1400 may be performed by control assembly 900or control assembly 1000, described above with reference to FIGS. 9-10.For example, process 1400 may be performed in part by the actuatorprocessing circuit 908 and/or the flow sensor processing circuit 910. Inother embodiments, process 1400 may be performed by the flow signalfiltering circuit 636 of actuator 602, described above with reference toFIG. 6. For the purposes of simplicity, process 1400 will be describedexclusively with reference to control assembly 900. Process 1400 isshown to commence with steps 1402 and 1404, in which an actuatorsetpoint and a noisy flow measurement are received at the flow sensorprocessing circuit 910. In some embodiments, actuator setpoint isreceived from the actuator processing circuit 908. In some embodiments,the noisy flow measurement (which may also be designated a “raw” flowmeasurement) is received from sensor assembly 906 using ultrasonictransducers 924 and 926 and communicated to the flow sensor processingcircuit 910 through a wired or wireless connection. In some embodiments,a “noisy” flow measurement is defined as a flow measurement with avariance that exceeds a variance threshold value, or a signal to noiseratio that exceeds a predetermined signal to noise ratio thresholdvalue.

At step 1406, the actuator processing circuit 908 determines if thereceived actuator setpoint has changed by a threshold amount or moresince the last time the actuator setpoint was recorded (e.g., at a lasttime step). In response to the actuator processing circuit 908determining the actuator setpoint has not changed (or has changed anamount less than the threshold), the process continues with step 1408where the flow sensor processing circuit 910 continues to filter thenoisy flow measurement and generate a filtered flow rate measurementthat is then utilized by the feedback controller of the actuatorprocessing circuit 908 to generate a new actuator position setpoint. Insome embodiments, the threshold amount is an adjustable value orparameter.

However, returning to step 1406, if the flow sensor processing circuit910 determines the actuator setpoint received in step 1402 has changedat least the threshold amount since the last time step, process 1400continues with step 1410. At step 1410, the flow sensor processingcircuit 910 disables a flow measurement filter (e.g. a low pass filter),holds an existing flow measurement value, and/or drives the actuator tothe actuator position setpoint. Use of the existing flow measurementvalue when the actuator setpoint has changed prevents the feedbackcontroller of the actuator processing circuit 908 from controlling thevalve member 918 according to flow measurements that may be unstable dueto the change in the position of the valve member 918.

Process 1400 continues with step 1412, in which the actuator processingcircuit 908 determines if an actuator position measurement is within aspecified tolerance of the new actuator setpoint. For example theactuator processing circuit 908 may determine if the actuator is at theactuator position setpoint+/−a position deadband. In some embodiments,the deadband is or is determined based on a dynamically adjustableparameter. The deadband may be a dynamic deadband and actuatorprocessing circuit 908 may use proportional variable deadband control(PVDC) as described in greater detail with reference to U.S. patentapplication Ser. No. 15/908,041, filed Feb. 28, 2018, the entiredisclosure of which is incorporated by reference herein. In response tothe actuator processing circuit 908 determining the actuator positionmeasurement is not within the specified tolerance, process 1400 revertsto step 1410. Conversely, in response to the actuator processing circuit908 determining the actuator position measurement is within thespecified tolerance, process 1400 concludes with step 1414, in which theflow sensor processing circuit 910 resets the filter and generates afiltered flow measurement. The filtered flow measurement may be utilizedby the feedback controller of the actuator processing circuit 908 togenerate a new actuator position setpoint. In some embodiments, the flowsensor processing circuit 910 resets the filter in response to valvemember 918 reaching its position setpoint.

The flow sensor processing circuit 910 may reset the filter (e.g., reseta Kalman filter) by resetting, adjusting, adaptively adjusting,changing, etc., a matrix that indicates a process noise covariance. Insome embodiments, one or more parameters of the filter are updated,adjusted, reset, changed, etc., once the valve member 918 reaches itsposition setpoint such that a memory of past measurements that arestored in or used by the filter are cleared. In this way, resetting thefilter ensures that previous measurements of the flow do not affect acurrent flow measurement or a current operation of the valve member 918.In some embodiments, resetting the filter clears turbulent events (e.g.,noisy measurements) that may be otherwise stored in the memory of thefilter. Resetting the filter may remove previously recorded noisymeasurements from consideration, thereby improving or increasing alikelihood of convergence of the filter to an actual value of the flowrate measurement. In some embodiments, the flow sensor processingcircuit 910 is configured to reset the filter in response to detectingthat the valve member 918 has reached its position setpoint (e.g.,reached a desired position).

Referring now to FIG. 15, a graph 1500 shows signals associated withvolumetric flow rate (e.g., values of the Y-axis in gallons per minute“gpm”) through a conduit (e.g., pipe 814, fixed pipe 1104, pipe 1208,etc.) with respect to samples (e.g., values of the X-axis) or time,according to some embodiments. Graph 1500 includes series 1502 andseries 1504, according to some embodiments. Series 1502 illustrates asensor signal (e.g., voltage values, volumetric flow rate valuesdetermined based on a sensor voltage, etc.) over time. In someembodiments, series 1502 represents sensor signals that are unfilteredor directly received from a sensor. For example, series 1502 mayrepresent sensor signals received from any of the sensors of ultrasonicflow sensor assembly 800, valve-coupled control assembly 900,valve-coupled control assembly 1000, ultrasonic flow sensor assembly1100, or ultrasonic flow sensor assembly 1200. In some embodiments,series 1502 represents sensor signals received or sampled directly fromany of ultrasonic transducers 804 and/or 810, transducers 924 and/or926, transducers 1114 and/or 1116, or ultrasonic transducers 1202 and/or1204.

As shown in FIG. 15 and represented by series 1502, the signal receiveddirectly from the sensor (e.g., a transducer, an ultrasonic transducer,etc.) may be noisy including peaks and valleys. Series 1504 illustratesseries 1502 (e.g., an unfiltered, raw, or otherwise unprocessed, sensorsignal received directly from a sensor) after the signal has been passedthrough a low-pass filter. Passing the signal represented by series 1502through a low-pass filter may attenuate noise that is present in thesignal, as shown in FIG. 15. In some embodiments, series 1504 representsthe signal received from one or more sensors (e.g., as represented byseries 1502) after the signal has been filtered (e.g., using any of thefiltering or statistical filtering techniques described herein) by anyof flow sensor processing circuit 910, etc. Series 1504 can represent asignal that is provided to and used by actuator processing circuit 908or any other processing circuit, computer, controller, device, etc.,that processes, uses, analyzes, etc., the signal represented by series1504 or uses the signal represented by series 1504 to control, adjust anoperation of, troubleshoot, etc., a mechanical transducer (e.g., motor912).

Referring now to FIG. 16, a graph 1600 shows volumetric flow ratethrough a conduit (e.g., pipe 814, fixed pipe 1104, pipe 1208, etc.)with respect to samples (e.g., values of the X-axis) or time, accordingto some embodiments. In some embodiments, graph 1600 includes series1602 and series 1604. Series 1602 shows a value of the volumetric flowrate that is measured using any of flow sensor assembly 800,valve-coupled control assembly 900, valve-coupled control assembly 1000,ultrasonic flow sensor assembly 1100, or ultrasonic flow sensor assembly1200. Series 1604 shows reference values of the volumetric flow ratethrough the conduit.

As shown in graph 1600, the flow rate that is measured using any of flowsensor assembly 800, valve-coupled control assembly 900, valve-coupledcontrol assembly 1000, ultrasonic flow sensor assembly 1100, and/orultrasonic flow sensor assembly 1200 (represented by series 1602) isoffset (e.g., higher) than the reference values of the volumetric flowrate through the conduit (represented by series 1604). For example, at afirst volumetric flow rate, the measured flow rate (series 1602) isgreater than the reference flow rate (series 1604) by an offset amount1606. At a second volumetric flow rate, the measured flow rate (series1602) is greater than the reference flow rate (series 1604) by an offsetamount 1608, according to some embodiments. At a third volumetric flowrate, the measured flow rate (series 1602) is greater than the referenceflow rate (series 1604) by an offset amount 1610. At a fourth volumetricflow rate, the measured flow rate (series 1602) is greater than thereference flow rate (series 1604) by an offset amount 1612. At a fifthvolumetric flow rate, the measured flow rate (series 1602) is greaterthan the reference flow rate (series 1604) by an offset amount 1614,etc.

Referring to FIGS. 5-7, 8-12, and 16, the offset amount (e.g., offsetamounts 1606-1614) increase with increased volumetric flow rate throughthe conduit. For example, at higher volumetric flow rates through theconduit, the measured flow rate (series 1602) may be offset further thanthe reference flow rate (series 1604). In some embodiments, any of theprocessing circuits, controllers, processors, etc., that are operativelyand/or communicably coupled with flow sensor 506, ultrasonic flow sensorassembly 800, flow sensor assembly 906, ultrasonic flow sensor assembly1100, and/or ultrasonic flow sensor assembly 1200 (or any of the sensorcomponents thereof) are configured to adjust the measured flow rate toaccount for offsets 1606-1614. In some embodiments, flow sensorprocessor 516, flow signal filtering circuit 636, processing circuit606, controller 704, and/or flow sensor processing circuit 910, (any ofwhich are referred to as “the processing circuit” for ease ofexplanation) are configured to adaptively adjust the measured flow rate.In some embodiments, the processing circuit is configured to determinean offset amount {dot over (V)}_(offset) and adjust (e.g., increase ordecrease) the measured flow rate by the offset amount.

In some embodiments, the offset amount is linearly and/or non-linearlyrelated to the measured flow rate. For example, the offset amount may beproportional to the measured flow rate (e.g., referred to as {dot over(V)}_(measured)) such that: {dot over (V)}_(offset)∝{dot over(V)}_(measured). In some embodiments, the processing circuit isconfigured to determine the offset amount using a predeterminedrelationship, function, equation, etc., and the measured flow rate. Theprocessing circuit may then adjust the measured flow rate using theoffset amount to account for offsets 1606-1614 for various flow rates.In some embodiments, the processing circuit is configured to adjust again of a filter (e.g., the Kalman filter) used by the processingcircuit based on the measured flow rate. For example, the processingcircuit may increase the gain of the filter with increased values of themeasured flow rate.

Referring now to FIGS. 5-7, 8-12, and 17, the processing circuit may beconfigured to enable/disable and/or activate/de-activate various signalprocessing (e.g., filtering techniques, adjustment techniques, adaptivefiltering, etc.) when the flow rate through the conduit is changing toachieve a faster signal response time to disturbances. FIG. 17 shows agraph 1700 including series 1702 and series 1704. Graph 1700 illustratesvalues of the volumetric flow rate through the conduit (the Y-axis) withrespect to samples (the X-axis), according to some embodiments. Series1702 shows the filtered signal over time with enable/disable, whileseries 1704 shows the filtered signal over time without enable/disable.As shown in graph 1700, when the processing circuit enables/disables thefiltering or signal processing techniques when the flow rate ischanging, the signal response to disturbances in the system isincreased. In some embodiments, the enable/disable feature is only usedwhen the flow sensor (e.g., flow sensor 506, ultrasonic flow sensorassembly 900, flow sensor assembly 906, ultrasonic flow sensor assembly1100, and/or ultrasonic flow sensor assembly 1200) is operatively orelectrically coupled with a processing circuit that controls or adjustsan operation of a valve (e.g., valve 904, etc.).

In some embodiments, “enabling” the filter includes using output datafrom the filter for control, display, etc., of any of flow sensor 506,ultrasonic flow sensor assembly 900, flow sensor assembly 906,ultrasonic flow sensor assembly 1100, and/or ultrasonic flow sensorassembly 1200 (or any other flow sensor assemblies, actuators, valves,motors, etc., described herein). In some embodiments, “disabling” thefilter includes using input data (e.g., raw sensor data) of the flowsensor (e.g., flow sensor 506, ultrasonic flow sensor assembly 900, flowsensor assembly 906, ultrasonic flow sensor assembly 1100, and/orultrasonic flow sensor assembly 1200) for display, etc., of the flowsensor assembly and/or an actuator, motor, valve, etc., of the flowsensor assembly. In some embodiments, “disabling” the filter results inusing position control only (e.g., moving the actuator to a newsetpoint) without using flow control (e.g., without using the flow ratefor control of the actuator). In this way, enabling or disabling thefilter does not necessarily mean that the filter does not process data,but rather that the processing circuit uses the inputs or the outputs ofthe data for different applications or functions differently.

Configuration of Exemplary Embodiments

The construction and arrangement of the systems and methods as shown inthe various exemplary embodiments are illustrative only. Although only afew embodiments have been described in detail in this disclosure, manymodifications are possible. For example, the position of elements may bereversed or otherwise varied and the nature or number of discreteelements or positions may be altered or varied. Accordingly, all suchmodifications are intended to be included within the scope of thepresent disclosure. The order or sequence of any process or method stepsmay be varied or re-sequenced according to alternative embodiments.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions and arrangement of the exemplaryembodiments without departing from the scope of the present disclosure.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media that can be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer or other machine with a processor. Combinationsof the above are also included within the scope of machine-readablemedia. Machine-executable instructions include, for example,instructions and data which cause a general purpose computer, specialpurpose computer, or special purpose processing machines to perform acertain function or group of functions.

Although the figures show a specific order of method steps, the order ofthe steps may differ from what is depicted. Also two or more steps maybe performed concurrently or with partial concurrence. Such variationwill depend on the software and hardware systems chosen and on designerchoice. All such variations are within the scope of the disclosure.Likewise, software implementations could be accomplished with standardprogramming techniques with rule based logic and other logic toaccomplish the various connection steps, processing steps, comparisonsteps and decision steps.

What is claimed is:
 1. A system for controlling a flow rate of a fluidthrough a valve, the system comprising: a controller configured to:receive a raw flow rate measurement from a flow rate sensor assemblyconfigured to measure the flow rate; apply a flow rate measurementfilter to the raw flow rate measurement to generate a filtered flow ratemeasurement; control actuation of an actuator configured to change theflow rate using the filtered flow rate measurement; and automaticallyadjust the flow rate measurement filter in response to detecting anevent that causes stoppage of the actuation of the actuator.
 2. Thesystem of claim 1, wherein the controller is further configured to:control actuation of the actuator using the raw flow rate measurementfor flow rate measured during actuation of the actuator to change theflow rate and using the filtered flow rate measurement for flow ratemeasured during stoppage of the actuation of the actuator.
 3. The systemof claim 1, wherein the flow rate measurement filter comprises a memoryof previously recorded values of the flow rate and the controller isconfigured to reset the flow rate measurement filter by updating one ormore parameters of a process noise covariance matrix in response todetecting the event that causes stoppage of the actuation of theactuator.
 4. The system of claim 1, wherein adjusting the flow ratemeasurement filter comprises clearing a memory of previously recordedvalues of the flow rate so that the previously recorded values of theflow rate are not used by the flow rate measurement filter to generatethe filtered flow rate measurement.
 5. The system of claim 1, whereinthe flow rate sensor assembly comprises a first ultrasonic transducerand a second ultrasonic transducer.
 6. The system of claim 5, whereinthe first ultrasonic transducer and the second ultrasonic transducer arelocated such that a first portion of a flow path between the firstultrasonic transducer and the second ultrasonic transducer is parallelto the flow of fluid, and a second portion of the flow path between thefirst ultrasonic transducer and the second ultrasonic transducer isperpendicular to the flow of fluid.
 7. The system of claim 5, whereinthe first ultrasonic transducer and the second ultrasonic transducer arelocated such that the flow of fluid passes between the first ultrasonictransducer and the second ultrasonic transducer.
 8. The system of claim6, wherein a flow path between the first ultrasonic transducer and thesecond ultrasonic transducer is positioned at a first angle relative tothe flow of fluid.
 9. An ultrasonic flow sensor assembly configured tomeasure a flow of fluid through a conduit, the ultrasonic flow sensorassembly comprising: a first ultrasonic transducer and a secondultrasonic transducer fixedly coupled with the conduit and separatedfrom each other by a distance less than or substantially equal to twicea diameter of the conduit; a processing circuit configured to: operatethe first ultrasonic transducer to emit an ultrasonic signal along aflow path of the fluid in the conduit by providing a voltage or currentto the first ultrasonic transducer; receive a voltage or current fromthe second ultrasonic transducer in response to the second ultrasonictransducer receiving the ultrasonic signal emitted by the firstultrasonic transducer; obtain a raw measurement of a flow rate of thefluid in the conduit using the received voltage or current; and generatea filtered measurement of the flow rate of the fluid using a filter andthe raw measurement.
 10. The ultrasonic flow sensor assembly of claim 9,further comprising a structural member, separate from the conduit,extending between the first ultrasonic transducer and the secondultrasonic transducer, wherein the structural member is fixedly coupledwith the first ultrasonic transducer and the second ultrasonictransducer and maintains a fixed distance between the first ultrasonictransducer and the second ultrasonic transducer.
 11. The ultrasonic flowsensor assembly of claim 9, wherein the first ultrasonic transducer andthe second ultrasonic transducer are each configured to: receive anultrasonic signal within the conduit and convert the received ultrasonicsignal to a voltage or current; and receive a voltage or current andemit an ultrasonic signal at least partially along the flow path of thefluid in the conduit.
 12. The ultrasonic flow sensor assembly of claim9, further comprising an actuator operatively coupled with theprocessing circuit, wherein the processing circuit is configured tooperate the actuator to affect the flow rate of the fluid through theconduit using the filtered measurement of the flow rate of the fluid.13. The ultrasonic flow sensor assembly of claim 12, wherein theprocessing circuit is configured to use the filtered measurement of theflow rate of the fluid to operate the actuator when the actuator iswithin a position setpoint plus or minus a deadband and maintain acurrent value of the position setpoint when the actuator is outside ofthe deadband of the position setpoint.
 14. The ultrasonic flow sensorassembly of claim 12, wherein the processing circuit is configured toreset the filter in response to the actuator reaching a positionsetpoint or in response to an event that causes stoppage of theactuator, wherein resetting the filter comprises clearing a memory ofthe filter of previously obtained values of the raw measurement of theflow rate.
 15. The ultrasonic flow sensor assembly of claim 14, whereinclearing the memory comprises adjusting one or more parameters of thefilter.
 16. The ultrasonic flow sensor assembly of claim 9, furthercomprising a first acoustic reflector and a second acoustic reflector,wherein the first and second acoustic reflectors are configured tocooperatively direct the ultrasonic signal emitted by the firstultrasonic transducer along the flow path of the fluid and to the secondultrasonic transducer.
 17. The ultrasonic flow sensor assembly of claim16, wherein the first ultrasonic transducer and the second ultrasonictransducer are oriented to emit and receive the ultrasonic signal in adirection perpendicular to the flow path of the fluid.
 18. Theultrasonic flow sensor assembly of claim 9, wherein the first ultrasonictransducer and the second ultrasonic transducer are positioned onopposite sides of the conduit and the first ultrasonic transducer isconfigured to emit the ultrasonic signal towards the second ultrasonictransducer along a path angularly offset from the flow path of thefluid.
 19. A method for measuring a flow rate of fluid through aconduit, the method comprising: measuring the flow rate of the fluid andgenerating a raw flow rate measurement; applying a flow rate measurementfilter to the raw flow rate measurement to generate a filtered flow ratemeasurement; controlling actuation of an actuator to change the flowrate using the filtered flow rate measurement; and automaticallyadjusting the flow rate measurement filter in response to detecting anevent that causes stoppage of the actuation of the actuator.
 20. Themethod of claim 19, further comprising: controlling actuation of theactuator using the raw flow rate measurement for flow rate measuredduring actuation of the actuator to change the flow rate and using thefiltered flow rate measurement for flow rate measured during stoppage ofthe actuation of the actuator.